Is there ever a BAD time to add soil conditioner?

10 years ago

Subject says it all. Is there a bad (or unnecessary/inappropriate) time to add soil conditioner to your garden? I'm planning my garden for this year and it will be the second year for it in this spot. It's a little on they clay-ey side but we still got (in my opinion) awesome yields last year.

Could it be worth adding? Can it do any harm?

Featured Answer

gardengal48 (PNW Z8/9)

10 years ago

There IS a difference between a soil conditioner and compost, but they are sometimes used to the same purpose. Soil conditioners are typically recommended to loosen/lighten heavy clay soils. They are often bark-based but sometimes with things like gypsum or crushed stone added as well. The bark works to provide pore space or those empty areas between soil particles that allow for oxygen and water penetration. This assists with drainage - something often lacking in heavy or clay soils - and as the bark is an organic substance, its gradual decompostion further improves the soil and attracts soil organisms.

Compost is just mostly decomposed organic matter. It too can lighten a heavy soil and help to improve drainage but the effect tends to be not very long-lived. As it is usually of more uniform particle size and fairly well decomposed already, it does not provide the same degree of aeration the larger, more barky soil conditioners do. On the other hand, it is far more nutrient rich than a soil conditioner and can be used almost as a fertilizer substitute.

And it is also important to differentiate between a soil 'conditioner' and a soil 'amendment'. Soil amendment covers a whole lotta different additives that may or may not be needed, including various fertilizers, root growth stimulators and assorted fungal innoculants. A soil conditioner is a very specific type of soil amendment. It is usually added when you first begin to amend your soil or create a new planting bed, should your existing soil conditions require it. Compost can be added at any time - when amending a new planting area, as a mulch or as a nutrient rich top dressing. Adding any type of amendment to individual planting holes is something that is no longer often recommended but depends a lot on the type of plant being planted :-) Annuals and veggies and many perennials - OK. Trees and shrubs - not a good idea.

Comments (9)

paleogardener
10 years ago
My soil is clay-ey as well and I don't know of a bad time to add compost (soil conditioner). I add whenever I have the finish matl. to do so. All my beds & garden get several applications over a year. This is zone 9 with dry hot summers & chilly wet winters (but not this one...) if that makes a difference or not I don't know.
Hope that helps in some way.
trpnbils
Original Author
10 years ago
Ok so that leads me to another question. Is there a difference between soil conditioners and compost? I would believe that there is, based on the fact that you can buy each separately, but I couldn't back that up with solid evidence. I mean obviously if you're adding compost, you're "conditioning" in a sense, but is there something else to a conditioner?
paleogardener
10 years ago
Compost that I have made is the only conditioner I have ever used so I'm not qualified answer about bagged soil conditioners. I'm sure others will weigh in.
Kimmsr
10 years ago
No, there is never a bad time to add "soil conditioners" to soil.
Every "soil conditioner" I have ever looked at is organic matter. Compost s organic matter. The only difference I have ever seen is price with what is labeled "soil conditioner" priced about twice as much as compost.
lazy_gardens
10 years ago
Is there a bad (or unnecessary/inappropriate) time to add soil conditioner to your garden?

Unless it's compost, yes. Most of the time they are not needed, they are just heavily marketed to people who feel the urge to DO SOMETHING.

I add soil sulfur to my garden because we KNOW we need it to lower pH and unlock some of the iron in the extremely alkaline desert dirt.

But "humic acid", "microbiota", "mycorrhyza mix #9" .... and any and all of those things you attach to the end of a hose and spray on the dirt ... heck no. it's Pixie dust and the only thing it improves is the vendor's bank balance.

If your plants did well, you don't need additives. Start a compost heap, make your own compost and get the urge to do something taken care of that way.
trpnbils
Original Author
10 years ago
I have a compost pile but it was spread over the garden at the end of the season and tilled under. We also started vermicomposting indoors over the winter but don't have an appreciable amount. I'm thinking with that I might just take a handful of it and put it in the holes as I plant this year.
toxcrusadr
10 years ago
I totally agree with the 'compost will do the same thing' comments.

And, it's impossible to know whether a product is worthwhile unless you know exactly what is in it, and what condition you are trying to 'treat'.
subk3
10 years ago
The bags of "soil conditioner" I buy at Lowes are simply pine bark fines. I have a horse operation so use composted (or mostly but not entirely composted) horse manure and stall leavings on all my beds--perennials, vegetable, roses, foundation planting. Once I have an established bed, I use it in the same way most people use mulch. In areas that need a more finished look I'll top the layer of compost off with the soil conditioner because it is so much more attractive.

Because of my over abundant availability of compost I don't mix soil conditioners into the soil because as others have said the compost can do the same thing and it has added benifits that the conditioner doesn't include. I would think though that a soil conditioner that is wood product might give you some nitrogen tie up issues if too much of it is dug into the soil.

I have also used soil conditioner on perennial gardens as the sole source of mulch. It breaks down quicker than the large wood chunk mulch, but I very much liked the results after several years of using it on top of the soil.